Researchers at the University of Texas Health Science Center, San Antonio, report, in a study published in the journal Cancer Prevention Research, that concurrent treatments combining topically applied resveratrol with topical or dietary grape seed extract, and calcium D-glucarate and ellagic acid supplements suppress skin cancer and inflammation. The scientists believe this research could be used in the future to develop supplements, creams and sunscreens to protect skin.

The materials were derived from natural plant sources, according to a university press announcement, and included: resveratrol from the skin of red grapes; grape seed extract; calcium D-glucarate, a salt of D-glucaric acid, which is present in the human bloodstream and in many fruits and vegetables; and ellagic acid from various berries and walnuts. This combination was required reportedly due to the different mechanisms of action of each substance.

The substances were tested on mice that had been genetically manipulated to be sensitive to skin cancer initiation and promotion/progression. Thomas Slaga, PhD, the team leader, developed SENCAR, the mouse model to test for skin cancer treatments. He and colleagues Zbigniew Walaszek, PhD, and Magdalena Kowalczyk, PhD, administered the agents both topically and systemically. In one study, skin cancer was induced on the backs of rodents twice weekly for four weeks. At the same time, researchers applied topical resveratrol and fed the mice diets including various combinations of the plant substances.

The team evaluated several outcomes, including thickness in the outer layer of the skin since an increase in thickness indicates that precancerous cells are multiplying. Researchers also monitored mutations in Ha-ras, an oncogene that is a biomarker of cancer initiation, and inflammation, which is important in tumor promotion. Even low doses of the plant agent combinations produced protective effects, while the plant substances given individually produced markedly less benefits.

The researchers noted in the press announcement that the combination of substances could be effective on other cancers involving epithelial cells, such as lung cancer. In addition, such treatments may help protect individuals that have already initiated the malignant formation of cells by smoking or sunbathing from developing certain cancers.

The team continues to look for the best combinations of these natural agents to suppress the mechanisms involved in skin cancer development. Next, the team plans to use a UVB light model of skin cancer initiation to confirm these findings. The ongoing work is supported by two grants from the National Institutes of Health.